Test: Biodiversity & Its Importance - NEET MCQ

The “active chemical drug reserpine” is obtained from Rauwolfia.
Reserpine is an “indole alkaloid” obtained from the roots of “Rauwolfia serpentine” and “Rauwolfia vomitoria”. It was first isolated from the dried roots of Rauwolfia in 1950. It is widely used as an antihypertensive and antipsychotic drug. It is an adrenergic blocker.

Rauwolfia serpentina:

Topic in NCERT: Genetic diversity

Line in NCERT: "the genetic variation shown by the medicinal plant rauwolfia vomitoria growing in different himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces."

The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country. 

Topic in NCERT: Loss of biodiversity

Line in NCERT: "more than 15,500 species world-wide are facing the threat of extinction."

• IUCN is International Union for Conservation of Nature, this system is designed to determine the relative risk of extinctin
• The main purpose of the IUCN Red List or red data book is to catalogue and highlight those plants, fungi and animals that are facing a higher risk of global extinction (i.e. those listed as Critically Endangered, Endangered and Vulnerable).

Topic in NCERT: How many species are there on earth and how many in india?

Line in NCERT: "according to the international union for conservation of nature and natural resources (iucn) (2004), the total number of plant and animal species described so far is slightly more than 1.5 million..."

Species of reptiles, amphibians and other vertebrates are becoming extinct in Haiti as deforestation has claimed more than 99 percent of the country's original wooded areas.

Topic in NCERT: Causes of biodiversity losses

Line in NCERT: "habitat loss and fragmentation: this is the most important cause driving animals and plants to extinction."

According to the IUCN regional red listing guidelines: 
- 12% of all the birds species
- 23% of all mammals species
- 31% of all gymnosperms species
- 32% of all amphibian species

These species face the threat of extinction in the world and have the highest percentage of endangered species, and the threats including habitat loss, fragmentation and degradation, pollution, climate change, and invasive alien species.

Topic in NCERT: Biodiversity and conservation

Line in NCERT: "32 per cent of all amphibian species... face the threat of extinction."

Paul Ehrlich's rivet popper hypothesis compares an ecosystem to an airplane, where species are like rivets holding it together. Key species (rivets critical to structure) are more vital, and their loss poses a greater threat than less critical species (Option A is correct). Initially, the loss of a few species may not disrupt ecosystem function (Option B is correct), but continuous loss over time can lead to ecosystem collapse (Option C is correct). However, the hypothesis does not suggest that the loss of less significant species alone leads to critical damage; it emphasizes the cumulative effect and the importance of key species. Thus, Option D is incorrect.

Topic in NCERT: Loss of biodiversity

Line in NCERT: "loss of rivets on the wings (key species that drive major ecosystem functions) is obviously a more serious threat to flight safety than loss of a few rivets on the seats or windows inside the plane."

Statement a: Biodiversity decreases from low to high latitudes (e.g., tropics to poles), as tropical regions have higher species diversity. Thus, statement a is incorrect.
Statement b: In Paul Ehrlich’s rivet popper hypothesis, rivets on critical parts like wings represent key species that are essential for ecosystem stability. This is correct.
Statement c: India is a megadiverse country, contributing approximately 8.1% to global species diversity, which aligns with estimates. This is correct.
Since b and c are correct, the answer is Option A (b and c only).

Topic in NCERT: Biodiversity and conservation

Line in NCERT: "although india has only 2.4 per cent of the world's land area, its share of the global species diversity is an impressive 8.1 per cent."

The species-area relationship states that the number of species (species richness) increases with the size of the area, typically following a power-law relationship (Option A is correct). Option B is a general ecological principle but not a core part of the species-area relationship. Option C is incorrect, as endemism depends on geographic isolation, not area size. Option D is incorrect, as larger areas typically have lower extinction rates due to greater habitat stability and population sizes. Thus, Option A is the most accurate.

Topic in NCERT: Species-area relationships

Line in NCERT: "species richness increased with increasing explored area, but only up to a limit."

The species-area relationship is described by the power-law equation S = CA^Z, where S is species richness, A is area, C is a constant, and Z is the scaling exponent. On a logarithmic scale, this becomes a linear equation: logS = logC + ZlogA. This matches Option C, which correctly represents the relationship. Options A, B, and D do not align with the standard logarithmic form of the species-area relationship.

Topic in NCERT: Species-area relationships

Line in NCERT: "log s = log c + z log a"

The largely tropical Amazonian rain forest in South America has the greatest biodiversity on earth- it is home to more than 40,000 species of plants, 3,000 of fishes, 1,300 of birds, 427 of mammals, 427 of amphibians, 378 of reptiles and of more than 1,25,000 invertebrates.

Topic in NCERT: Biodiversity and conservation

Line in NCERT: "the largely tropical amazonian rain forest in south america has the greatest biodiversity on earth- it is home to more than 40,000 species of plants, 3,000 of fishes, 1,300 of birds, 427 of mammals, 427 of amphibians, 378 of reptiles and of more than 1,25,000 invertebrates."